1. Field of the Invention
The invention pertains to a musical instrument with an acoustic transducer, which transforms an excitation signal generated by at least one resonator into an acoustic signal, and in which the acoustic transducer is provided with an adjustable oscillation profile, in which at least one profile parameter is defined by a reference profile of a reference instrument.
2. Description of the Related Art
The production of sound by a musical instrument usually occurs through the interaction of three individual components. First, an excitation occurs, by means of which an excitation energy is introduced into the instrument. This can be the bow of a violin, for example, or the hammer of a piano or the mouthpiece and reed of a saxophone. Another component involves the presence of one or more resonators, which determine the fundamental frequency of the individual tones. The resonators can have constant or variable properties.
Resonators are, for example, the strings of a violin or guitar or the variable air column of a saxophone. Together, the excitation energy introduced into the resonator, the exciting element, and the resonator lead to the production of sound.
The third component participating in the production of sound is a sound transducer or resonance body, which transforms the oscillatory energy provided by the instrument into sound levels of the surrounding air and as a result transports the oscillatory energy into the air with the greatest possible efficiency. These resonance bodies are, for example, the body of a violin, the bell of a saxophone, the pickup of an electric guitar, or the loudspeaker of a guitar amplifier.
The sound transducer or resonance body is usually an acoustic or electroacoustic impedance transducer and is typically designed so that the instrument will produce a high perceptible volume. In addition, the sound transducer or resonance body has the task of forming the frequency spectrum of the instrument, so that, in this way, the instrument will produce a beautiful and characteristic sound.
The character of the sound influenced by the resonance body is the essential factor in determining the perceived quality of a musical instrument and thus also the quality of a musical performance. The acoustic properties of the sound transducer are determined both by its geometry and by the selected materials.
From an acoustic standpoint, the individual sound character of an instrument is determined by the so-called “formants”. These formants are narrow-band peaks in the frequency spectrum and are usually independent of the pitch being played. The human ear reacts with great sensitivity to these formants by a process of pattern recognition, so that even musically untrained people are easily able to differentiate the sound of a violin from the sound of a viola, even though the instruments differ essentially only through the size of their sound bodies.
Because of the large number of physical parameters which determine the sound impression of a certain sound transducer or of the resonance body, it usually turns out also to be an extremely complicated matter to provide a resonance body with a precisely predetermined sound profile. Another essential problem is encountered when a relatively large number of resonance bodies are to be produced with essentially the same predetermined sound impressions.
It is known from DE 103 92 940 T5 that an acoustic signal generated by a sound transducer of a musical instrument can be modified. The sound transducer is provided with an adjustable oscillation profile. The oscillation signal is modified by the use of a signal processor.
US 2005/0045027 A1 describes a variable memory for frequency responses to be determined in order to adapt the sound of a musical instrument to other specified instruments. Corresponding stored frequency responses are called up and processed within the framework of a control process.
U.S. Pat. No. 6,740,805 B2 describes a process for radiating a previously recorded and stored spatial sound event. The sound event is recorded in a first step by the use of several microphones distributed in space, and then the recording is played back without the participation of any other musical instrument.
DE 20 2004 008 347 U1 describes a method for the algorithmic production of melodies under consideration of external factors.
In U.S. Pat. No. 5,578,548 A, a processing method is described for combining a frequency response of a sound body of a musical instrument with the frequency response of an excitation of the resonator. As a result of this combination, the required processor power and the memory capacity can be reduced.
U.S. Pat. No. 6,392,135 B1 describes a virtual musical instrument which can play back stored sound material in an adaptable manner.